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Syphilis Testing Points u If an individual has newly acquired syphilis, a treponemal test generally is positive before the non-treponemal test. u Example: a person has a primary syphilitic lesion for 5 days – the FTA may be reactive and the RPR non reactive.

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Reverse Sequence Syphilis Testing u Testing serum for syphilis first with a confirmatory test, generally a treponemal EIA (enzyme immunoassay), or chemiluminescence immunoassay (CIA). u If the treponemal EIA result is non-reactive the result is reported as negative – no further testing generally recommended.

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Reverse Sequence Syphilis Testing u If the treponemal EIA or CIA is reactive, the specimen is reflexed for an RPR. u If the RPR is reactive, the interpretation is past or present syphilis infection. If no treatment history—treat

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Reverse Sequence Syphilis Testing u If the RPR is non-reactive after a positive EIA or CIA, the specimen should be tested reflexively with another treponeme specific test, ideally TP-PA. If the TP-PA is non- reactive, the EIA is likely a false positive. u If the TP-PA is reactive, likely represents and old infection, or possibly a very new infection.

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Recent Examples u Patient presents with a rash, EIA is highly reactive > 8.0, reflexed RPR is 1:128; patient is treated as secondary syphilis. u Routine draw on a patient, EIA is reactive, reflexed RPR is non-reactive, TP-PA is non-reactive, the EIA result is considered false positive, patient not infected.

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CDC Recommendations u “CDC continues to recommend the traditional syphilis screening algorithm …, however, if reverse sequence screening is used, reactive sera by a treponemal test should be tested reflexively with a quantitative non-treponemal test.” For example, a RPR.